1. Field of the Invention
This invention relates to a fibre plate made up of a stack of rows of glass fibre bundles.
2. Description of the Related Art
Such a fibre plate is disclosed in British Patent Specification No. 1,470,889. It comprises a number of glass fibre bundles which are stacked in mutually orthogonal rows and columns and which each comprise a large number of glass fibres. Such fibre plates are cut from a fibre bundle stack, i.e. a rod composed of drawn and compressed glass fibres having a length of, for example, approximately 25 cm. All fibre plates cut from the same stack generally have the same properties to a great extent and also differences to some extent which may be defects or advantages. It is therefore useful, in particular in the manufacture of fibre plates, to identify in a simple manner from which stack an individual fibre plate has been cut. The cause of differences in individual plates can then often be traced rapidly because in many cases the cause originates from production conditions of the stack in question.